Hyperlipidemia is known to be a risk factor leading to various adult diseases, such as arteriosclerosis, cardio- and nephro-vascular diseases, diabetes, etc. The drugs for preventing or alleviating hyperlipidemia must have high safety because such drugs are likely to be used for a prolonged period of time in view of the nature of the disease. However, reports have been made on various side effects of nicotinic acid and derivatives thereof, dextran sulfate, and clofibrate and derivatives thereof heretofore known as antilipemic agents. Nicotinic acid and its derivatives, for example, produce side effects, such as pruritus and cutaneous flushing due to vasodilatation, gastrointestinal disorders, abnormalities in liver function and glucose intolerance. These drugs have many side effects further because they must be given at a large dose of at least 3 g/day. Furthermore clofibrate, which is typical of antilipemic agents which are widely used throughout the world, has recently been reported as having a carcinogenic activity as a serious side effect. Although animal tests or immunological investigations are being carried out on clofibrate by research institutes, the ultimate conclusions still remain to be made, so that clofibrate is clinically in limited use in various countries. In addition to the carcinogenic activity, clofibrate causes an increased sterol discharge, which reportedly increases the likelihood of gallstone formation. Thus the drug is likely to pose the problem of another side effect.
In view of the foregoing situation, we have conducted intensive research in order to provide more useful compounds having outstanding antilipemic activity and found that the compounds represented by the general formula (I) below fulfill this object. Thus the present invention has been accomplished.